This study analyzed insurance claims data from before and after the implementation of the Federal Mental Health Parity and Addiction Equity Act to examine the effects of parity on substance use disorder treatment. The results showed: 1) There was no change in the use of substance use disorder services or the total annual spending per enrollee on these services (which increased by only $10 per enrollee). 2) There was also no change in out-of-pocket spending for substance use disorder treatment users or several HEDIS quality measures related to identification and initiation of treatment. 3) This suggests that concerns about parity greatly increasing health care costs related to substance use disorder treatment were unfounded.

1. The effects of federal parity on substance use disorder treatment
Susan H. Busch, PhD;1 Andrew J. Epstein, PhD;2,3 Michael O. Harhay, MPH;2 David A. Fiellin, MD;1
Hyong Un, MD;4 Deane Leader Jr;4 Colleen L. Barry, PhD MPP5
1 Yale University; 2 University of Pennsylvania; 3 Veterans Affairs; 4 Aetna Inc; 5 Johns Hopkins University
 Analyses focused on enrollees in 10 states with
pre-existing SUD parity laws
 Under ERISA, fully insured plans are subject to
state parity laws, but self-insured plans are
exempt
 Compared pre-post changes in outcomes among
individuals newly subject to federal parity with
changes among individuals already subject to
pre-existing state SUD laws
 Used difference-in-differences models
 Controlled for enrollee gender, age and state
 Logistic regression for binary outcomes
 Two-part models for spending outcomes
 Method of recycled predictions and
nonparametric block bootstraps to calculate
effect size and confidence intervals
Methods Results
 Concern that federal parity would
greatly increase health care spending,
at least related to SUD treatment, was
unfounded
Policy Implications
 Historically, more stringent limits on coverage
for mental health and substance use disorder
(SUD) services
 In 2008, the U.S. Congress enacted the Paul
Wellstone and Pete Domenici Mental Health
Parity and Addiction Equity Act (MHPAEA)
 Required insurers to equalize private
insurance coverage for mental health and SUD
services with coverage for general medical
services
 Includes all financial requirements and
treatment limits
 Effective January 1, 2010
 Expected effects of parity on SUD treatment
are ambiguous, and no published information
is yet available
Background
 To examine the effects of the MHPAEA on
substance use disorder treatment
Objectives
Funded by NIH grants
NIDA DA026414 and
NIMH MH093414-01A1
 Aetna claims data for members continuously
enrolled during 2009 (pre) and 2010 (post)
 Annual total SUD spending per enrollee
includes all SUD-related inpatient, partial
hospitalization, intensive outpatient, and
outpatient services, and Rx drugs
Data and Measures
Baseline characteristics of study sample, 2009
Probability of use & spending per enrollee on
SUD services
Out-of-pocket (OOP) SUD spending per user
HEDIS measures: Identification
HEDIS measures: Treatment initiation
HEDIS measures: Treatment engagement
 No change in use of any SUD services
 Small increase in total annual SUD cost per
enrollee (i.e., $10 per enrollee per year)
 No change in OOP spending per SUD user
 No change in HEDIS measures
Summary of findings
Self insured
(N=162,761)
Fully insured
(N=135,578)
(p-value)
N (%) N (%)
Female 84,530 (54.1) 71,755 (52.9) p<0.001
Age p<0.001
18-31 years 40,520 (24.9) 35,205 (26.0)
32-46 years 63,903 (39.3) 50,870 (37.5)
47-62 years 58,338 (35.8) 49,503 (36.5)
Selected diagnoses
• Any substance use disorder
treatment
1,752 (1.1%) 912 (0.7%) p<0.001
• Any alcohol use
disorder treatment
653 (0.4) 342 (0.3) p<0.001
• Any illicit drug use disorder
treatment
1,099 (0.7) 570 (0.4) p<0.001
• Any opioid use
disorder treatment
323 (0.2) 166 (0.1) p<0.001
Change in value before
and after parity
Probability of
using SUD
treatment (%)
Total SUD
spending per
enrollee ($)
Probability
of using SUD
services (%)
Total SUD
spending
per enrollee ($)
Pre
parity
Post
parity
Pre
parity
Post
parity
95% CI 95% CI
Self insured
treatment
group
(N=162,761)
1.04 1.18 36.51 52.62
0.05
[-0.03, 0.12]
9.99
[2.54, 18.21]Fully insured
comparison
group
(N=135,578)
0.70 0.79 26.58 32.70
OOP spending for SUD
services
per user ($)
Change in value
before and after
parity ($)
Pre
parity
Post
parity
95% CI
Self insured
treatment group
449.48 538.70
39.00
[-71.05, 145.13]Fully insured
comparison group
572.23 622.45
Identification of SUD
service receipt (%)
Change in value
before and after
parity (%)
Pre
parity
Post
parity
95% CI
Self insured
treatment group
0.81 0.91
0.01
[-0.074, 0.94]Fully insured
comparison group
0.53 0.62
Treatment initiation (%)
Change in value before
and after parity
Pre
parity
Post
parity
% 95% CI
Self insured
treatment group
34.71 33.33
0.44 [-5.07, 6.40]
Fully insured
comparison group
32.63 30.81
Treatment engagement
(%)
Change in value before
and after parity
Pre
parity
Post
parity
% 95% CI
Self insured
treatment group
19.29 19.57
1.84 [-2.79, 6.65]
Fully insured
comparison group
19.40 17.84